It's way cool, but honestly... Unless you're planning to do a whole lot of them and really need to save time, you don't need that magical whack-a-mole style tool for the Z car valves. Where that style of tool would really shine is on overhead cam direct contact tappet style valves where the whole spring is down inside the tappet guide hole and you can't get a grip on the spring coils because the clearance is too tight. Like the one in the demo video.

 

How do I know? Because I spent last winter wrestling with the attached. Look at the upper left exhaust valve. That tool would have been a lot easier than the custom remover/installer that I made...
 

But isn't it more than that, the fact that it holds all of the bits together and there is no collets flying around has to count for something. I can get one on Amazon Canada with free shipping which means it is cheaper than the Sealy shown in post 3

So: This job took a while, I bought the magical wack-a-mole style and of course it does not clear the cam shaft. So I tried a few other models and there was the same problem with all of them. They all would work well if the cam was removed. So I ordered the Sealy from England. With the exchange rate and shipping it came out to just under $75 cdn. As well it took a few weeks to get here. Once I had the tool as everyone stated it was a nice quick afternoon job to replace all of the seals.

sorry you had to go through that, but glad you got it done. and if its any comfort, thanks to your post, others will avoid the same drama...